Systems for enabling participants of an event or an audience to enter responses are well known in the art. Such systems have wide applicability. For example, in a conference, conference participants can be provided with units or handsets which enable conference participants to fully participate by responding to questions individually, or by voting on motions raised during the conference. These systems also have applicability for any type of voting application such as audience voting for entertainment programmes. Such systems are also applicable in the field of education. Students can be provided with handsets for entering answers to questions. These systems enable immediate feedback to a presenter in a conference, a teacher, to entertainment programme producers, or to event organizers. Response systems can be generally divided into two categories: a hardwired system and a wireless system. A hardwired system is for example disclosed in U.S. Pat. Nos. 5,303,042 and 5,357,609. However, hardwired systems suffer from the disadvantage of requiring cables to connect each of the handsets to be used by participants. Thus these systems are less transportable and flexible. Wireless participant response systems can use any type of wireless communication system. For example, U.S. Pat. No. 5,870,214 discloses a system using infra-red as the transmission medium. This system is advantageous in that it is less prone to interference. The system does however require a line of sight between transmitters and receivers. Other wireless systems use radio frequency transmissions between transmitters and receivers. Such a system is disclosed in U.S. Pat. No. 5,273,437. This document discloses an audience participation system which uses the spread spectrum communication protocol for communication between keypads and a base station. Keypads are coded with characteristics to identify users to enable audience responses to be individually identified. This coding can be achieved by providing a bar code scanner to scan a conference badge worn by the user. To enable full participation the keypads are also provided with an audio capability enabling voice input to be transmitted over the wireless system.
Another RF wireless system is disclosed in U.S. Pat. No. 5,724,357 in which voice responses and keypad responses can be transmitted from handsets to a system controller. In this system code can be downloaded to configure handsets. However, a separate system controller is required.